SpringCloud/spring-cloud-commons
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Sync docs from master to gh-pages

Browse Source
This commit is contained in:
buildmaster
2018-06-07 18:32:34 +00:00
parent f13eebf64a
commit 5c5e39fce3
4 changed files with 20 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
multi/multi__spring_cloud_context_application_context_services.html
View File

@@ -55,7 +55,9 @@ For instance, you can insert additional properties from a different server or fr
}
}</pre><p>The <code class="literal">Environment</code> that is passed in is the one for the <code class="literal">ApplicationContext</code> about to be created&#8201;&#8212;&#8201;in other words, the one for which we supply additional property sources for.
It already has its normal Spring Boot-provided property sources, so you can use those to locate a property source specific to this <code class="literal">Environment</code> (for example, by keying it on <code class="literal">spring.application.name</code>, as is done in the default Spring Cloud Config Server property source locator).</p><p>If you create a jar with this class in it and then add a <code class="literal">META-INF/spring.factories</code> containing the following, the <code class="literal">customProperty</code> <code class="literal">PropertySource</code> appears in any application that includes that jar on its classpath:</p><pre class="screen">org.springframework.cloud.bootstrap.BootstrapConfiguration=sample.custom.CustomPropertySourceLocator</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_environment_changes" href="#_environment_changes"></a>1.7&nbsp;Environment Changes</h2></div></div></div><p>The application listens for an <code class="literal">EnvironmentChangeEvent</code> and reacts to the change in a couple of standard ways (additional <code class="literal">ApplicationListeners</code> can be added as <code class="literal">@Beans</code> by the user in the normal way).
It already has its normal Spring Boot-provided property sources, so you can use those to locate a property source specific to this <code class="literal">Environment</code> (for example, by keying it on <code class="literal">spring.application.name</code>, as is done in the default Spring Cloud Config Server property source locator).</p><p>If you create a jar with this class in it and then add a <code class="literal">META-INF/spring.factories</code> containing the following, the <code class="literal">customProperty</code> <code class="literal">PropertySource</code> appears in any application that includes that jar on its classpath:</p><pre class="screen">org.springframework.cloud.bootstrap.BootstrapConfiguration=sample.custom.CustomPropertySourceLocator</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_logging_configuration" href="#_logging_configuration"></a>1.7&nbsp;Logging Configuration</h2></div></div></div><p>If you are going to use Spring Boot to configure log settings than
you should place this configuration in `bootstrap.[yml | properties]
if you would like it to apply to all events.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_environment_changes" href="#_environment_changes"></a>1.8&nbsp;Environment Changes</h2></div></div></div><p>The application listens for an <code class="literal">EnvironmentChangeEvent</code> and reacts to the change in a couple of standard ways (additional <code class="literal">ApplicationListeners</code> can be added as <code class="literal">@Beans</code> by the user in the normal way).
When an <code class="literal">EnvironmentChangeEvent</code> is observed, it has a list of key values that have changed, and the application uses those to:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">Re-bind any <code class="literal">@ConfigurationProperties</code> beans in the context</li><li class="listitem">Set the logger levels for any properties in <code class="literal">logging.level.*</code></li></ul></div><p>Note that the Config Client does not, by default, poll for changes in the <code class="literal">Environment</code>.
Generally, we would not recommend that approach for detecting changes (although you could set it up with a
<code class="literal">@Scheduled</code> annotation).
@@ -64,7 +66,7 @@ Note that those APIs are public and part of core Spring).
You can verify that the changes are bound to <code class="literal">@ConfigurationProperties</code> beans by visiting the <code class="literal">/configprops</code> endpoint (a normal Spring Boot Actuator feature).
For instance, a <code class="literal">DataSource</code> can have its <code class="literal">maxPoolSize</code> changed at runtime (the default <code class="literal">DataSource</code> created by Spring Boot is an <code class="literal">@ConfigurationProperties</code> bean) and grow capacity dynamically.
Re-binding <code class="literal">@ConfigurationProperties</code> does not cover another large class of use cases, where you need more control over the refresh and where you need a change to be atomic over the whole <code class="literal">ApplicationContext</code>.
To address those concerns, we have <code class="literal">@RefreshScope</code>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_refresh_scope" href="#_refresh_scope"></a>1.8&nbsp;Refresh Scope</h2></div></div></div><p>When there is a configuration change, a Spring <code class="literal">@Bean</code> that is marked as <code class="literal">@RefreshScope</code> gets special treatment.
To address those concerns, we have <code class="literal">@RefreshScope</code>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_refresh_scope" href="#_refresh_scope"></a>1.9&nbsp;Refresh Scope</h2></div></div></div><p>When there is a configuration change, a Spring <code class="literal">@Bean</code> that is marked as <code class="literal">@RefreshScope</code> gets special treatment.
This feature addresses the problem of stateful beans that only get their configuration injected when they are initialized.
For instance, if a <code class="literal">DataSource</code> has open connections when the database URL is changed via the <code class="literal">Environment</code>, you probably want the holders of those connections to be able to complete what they are doing.
Then, the next time something borrows a connection from the pool, it gets one with the new URL.</p><p>Sometimes, it might even be mandatory to apply the <code class="literal">@RefreshScope</code>
@@ -81,9 +83,9 @@ To refresh an individual bean by name, there is also a <code class="literal">ref
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> include</span>: refresh</pre><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p><code class="literal">@RefreshScope</code> works (technically) on an <code class="literal">@Configuration</code> class, but it might lead to surprising behavior.
For example, it does not mean that all the <code class="literal">@Beans</code> defined in that class are themselves in <code class="literal">@RefreshScope</code>.
Specifically, anything that depends on those beans cannot rely on them being updated when a refresh is initiated, unless it is itself in <code class="literal">@RefreshScope</code>.
In that case, it is rebuilt on a refresh and its dependencies are re-injected. At that point, they are re-initialized from the refreshed <code class="literal">@Configuration</code>).</p></td></tr></table></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_encryption_and_decryption" href="#_encryption_and_decryption"></a>1.9&nbsp;Encryption and Decryption</h2></div></div></div><p>Spring Cloud has an <code class="literal">Environment</code> pre-processor for decrypting property values locally.
In that case, it is rebuilt on a refresh and its dependencies are re-injected. At that point, they are re-initialized from the refreshed <code class="literal">@Configuration</code>).</p></td></tr></table></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_encryption_and_decryption" href="#_encryption_and_decryption"></a>1.10&nbsp;Encryption and Decryption</h2></div></div></div><p>Spring Cloud has an <code class="literal">Environment</code> pre-processor for decrypting property values locally.
It follows the same rules as the Config Server and has the same external configuration through <code class="literal">encrypt.*</code>.
Thus, you can use encrypted values in the form of <code class="literal">{cipher}*</code> and, as long as there is a valid key, they are decrypted before the main application context gets the <code class="literal">Environment</code> settings.
To use the encryption features in an application, you need to include Spring Security RSA in your classpath (Maven co-ordinates: "org.springframework.security:spring-security-rsa"), and you also need the full strength JCE extensions in your JVM.</p><p>If you get an exception due to "Illegal key size" and you use Sun&#8217;s JDK, you need to install the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files.
See the following links for more information:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><a class="link" href="http://www.oracle.com/technetwork/java/javase/downloads/jce-6-download-429243.html" target="_top">Java 6 JCE</a></li><li class="listitem"><a class="link" href="http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html" target="_top">Java 7 JCE</a></li><li class="listitem"><a class="link" href="http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html" target="_top">Java 8 JCE</a></li></ul></div><p>Extract the files into the JDK/jre/lib/security folder for whichever version of JRE/JDK x64/x86 you use.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_endpoints" href="#_endpoints"></a>1.10&nbsp;Endpoints</h2></div></div></div><p>For a Spring Boot Actuator application, some additional management endpoints are available. You can use:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">POST</code> to <code class="literal">/actuator/env</code> to update the <code class="literal">Environment</code> and rebind <code class="literal">@ConfigurationProperties</code> and log levels.</li><li class="listitem"><code class="literal">/actuator/refresh</code> to re-load the boot strap context and refresh the <code class="literal">@RefreshScope</code> beans.</li><li class="listitem"><code class="literal">/actuator/restart</code> to close the <code class="literal">ApplicationContext</code> and restart it (disabled by default).</li><li class="listitem"><code class="literal">/actuator/pause</code> and <code class="literal">/actuator/resume</code> for calling the <code class="literal">Lifecycle</code> methods (<code class="literal">stop()</code> and <code class="literal">start()</code> on the <code class="literal">ApplicationContext</code>).</li></ul></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>If you disable the <code class="literal">/actuator/restart</code> endpoint then the <code class="literal">/actuator/pause</code> and <code class="literal">/actuator/resume</code> endpoints
See the following links for more information:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><a class="link" href="http://www.oracle.com/technetwork/java/javase/downloads/jce-6-download-429243.html" target="_top">Java 6 JCE</a></li><li class="listitem"><a class="link" href="http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html" target="_top">Java 7 JCE</a></li><li class="listitem"><a class="link" href="http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html" target="_top">Java 8 JCE</a></li></ul></div><p>Extract the files into the JDK/jre/lib/security folder for whichever version of JRE/JDK x64/x86 you use.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_endpoints" href="#_endpoints"></a>1.11&nbsp;Endpoints</h2></div></div></div><p>For a Spring Boot Actuator application, some additional management endpoints are available. You can use:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">POST</code> to <code class="literal">/actuator/env</code> to update the <code class="literal">Environment</code> and rebind <code class="literal">@ConfigurationProperties</code> and log levels.</li><li class="listitem"><code class="literal">/actuator/refresh</code> to re-load the boot strap context and refresh the <code class="literal">@RefreshScope</code> beans.</li><li class="listitem"><code class="literal">/actuator/restart</code> to close the <code class="literal">ApplicationContext</code> and restart it (disabled by default).</li><li class="listitem"><code class="literal">/actuator/pause</code> and <code class="literal">/actuator/resume</code> for calling the <code class="literal">Lifecycle</code> methods (<code class="literal">stop()</code> and <code class="literal">start()</code> on the <code class="literal">ApplicationContext</code>).</li></ul></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>If you disable the <code class="literal">/actuator/restart</code> endpoint then the <code class="literal">/actuator/pause</code> and <code class="literal">/actuator/resume</code> endpoints
will also be disabled since they are just a special case of <code class="literal">/actuator/restart</code>.</p></td></tr></table></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="multi_pr01.html">Prev</a>&nbsp;</td><td width="20%" align="center">&nbsp;</td><td width="40%" align="right">&nbsp;<a accesskey="n" href="multi__spring_cloud_commons_common_abstractions.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">&nbsp;</td><td width="20%" align="center"><a accesskey="h" href="multi_spring-cloud-commons.html">Home</a></td><td width="40%" align="right" valign="top">&nbsp;2.&nbsp;Spring Cloud Commons: Common Abstractions</td></tr></table></div></body></html>